• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.639-640
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• 2009

• Proceedings of the Korea Technology Innovation Society Conference
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• 2004.11a
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• pp.32-43
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• 2004

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.4
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• pp.654-666
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• 1995

R502 has been extensively used as a working fluid in transport refrigerating vehicles and low temperature refrigerating machines but is to be phased out by the end of 1995 due to ozone layer depletion problem. In this study, both theoretical cycle analysis and experiments were carried out to examine the best substitutes for R502. Theoretical results indicate that the alternatives available in the market today may replace R502 without significant changes in the system without suction line heat exchanger(SLHX). When the system contains a SLHX, however, COPs of the alternatives increase up to approximately 15~20% than those without the SLHX. But simultaneously, the discharge temperatures of the compressor also increrease significantly with the SLHX. Actual test results obtained from the experiment with a transport vehicle's refrigerator indicate the similar trend as those of the theoretical results. Especially, HFCs and their mixtures show lower discharge temperature than those of R502, which is one of the desirable features. Further research is needed to study the effect of the SLHX on the performance of the real machine as well as on the oil return for reliability of the system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.48
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• pp.291-297
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• 1998

This paper considers the determination of the priority of investment on R&D planning on nuclear power technology using AHP. Due to the complexity of problem, the hierarchy was divided into two parts; main hierarchy and sub-hierarchies. The result shows that the priority of technology options of evolutionary reactor and safety evaluation was higher than that of others.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.2
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• pp.152-161
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• 2009

Insider threat is becoming a very serious issue in most organizations and management is responsible for security implementation. This study is to develop a personnel security management indicators in the areas of Personnel Assurance, Personnel Competence, and Security Environment and protection against insider threats. In this study, the information security management system.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.2
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• pp.123-129
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• 2017

Objectives: The purpose of this study is to enhance the application of analytical method of polar solvents(alcohols) by GCOTC (gas chromatography open tubular column) through the system suitability test(SST) to estimate the whole chromatographic system performance(integral part). Methods: To perform the SST, carried out repeatability(n=6) as analytical method of polar solvents by GCOTC, got the retention time($t_R$), standard deviation(${\sigma}_{n-1}$) of $t_R$, baseline width($w_b=4{\sigma}_{n-1}$) and calculated dead time($t_m$) by $v_m=d^2{\pi}L(f/4)$ and $v_m=t_m$ x flow rate. Results: In this experiment, obtained the basic data, there were $t_m=2$ min, methanol($t_R=3.569$, ${\sigma}_{n-1}=0.01$, $w_b=0.04$), ethanol ($t_R=3.892$, ${\sigma}_{n-1}=0.004$, $w_b=0.016$), isopropanol($t_R=4.209$, ${\sigma}_{n-1}=0.004$, $w_b=0.016$). By using these data, calculated the corrected retention time($t_R{^{\prime}}$), capacity factor(k), separation factor(${\alpha}$), number of theoretical plate(n) and resolution($R_s$) for SST and got the good results. Conclusions: Through the SST, could reconfirm the whole chromatographic performance system(integral part) for analytical method of polar solvents by GCOTC. Therefore, this analytical method expect to be widely applied at the related areas.

• Bulletin of the Korean Chemical Society
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• v.4 no.3
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• pp.103-114
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• 1983

The NMR shift arising from the electron angular momentum and the electron spin dipolar-nuclear spin angular momentum interaction has been examined for a $3d_1$ system in a strong octahedral crystal field when the threefold axis is chosen as the quantization axis. To investigate the NMR shift in this situation, first, we have extended the evaluation of the hyperfine integrals to any pairs of 3d orbitals adopting a general method which is applicable to a general vector R, pointing in arbitrary direction in space. Secondly, a general expression using a nonmultipole technique is derived for the NMR shift resulting from the electron angular momentum and the electron spin dipolar-nuclear spin angular momentum interactions. From this expression all the multipolar terms are determined. ${\Delta}B/B$ for the $3d_1$ system in this case is compared with that for the 3d1 system when the z axis is chosen as the quantization axis. When we choose the threefold axis as the quantization axis, it is found that along the , and axes, ${\Delta}B/B$ values are significantly different from each other and along the , <-1-1-1>, <-11-1>, , <-1-11>, , and <-111> axes, ${\Delta}B/B$ values are however the same. We also find that the 1/R7 term contributes dominantly to the NMR shift for all values of R. When 1/$R^5$ term is included, there is good agreement between the exact solution and the multipolar terms when $R\; {\leqslant}\;0.35\;nm.$.

• The Journal of Industrial Distribution & Business
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• v.10 no.8
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• pp.55-65
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• 2019

Purpose - Recently, the fourth industrial revolution is rapidly progressing, and the central government-led innovation system is not able to flexibly cope with changes in science and the economy and society. To solve these problems, it is necessary for local governments, which can easily identify and flexibly respond to local sites, to become self-centered and ready to respond more quickly to massive changes. Through this research, this study investigated the awareness of the elements of Jeonnam Province's capabilities in the field of science and technology policy, the importance of R&D, and how network cooperation among the base institutions might affect performance. Research design, data, and methodology - In fact, the data used in this study only 115 people were polled, excluding five who did not respond to the necessary variables. The methods of the survey were sampled, and the means of the survey were investigated via a self-contained electronic file (e-mail). Statistical analysis, including hypothesis verification, was performed by SPSS 19. The regression analysis was used. Results - All factors significantly affect performance by dividing them into five sub-fields: R&D strategic establishment, R&D demand survey, R&D planning, R&D evaluation, and R&D project management. These results suggest the importance and need for local scientific technology policy capabilities. Besides, it was confirmed that the relationship between regional science and technology policy capabilities and performance was moderated by the recognition of the importance of science technology and network cooperation among the core organizations. Conclusions - As a result, independent variables regarding the capabilities of each scientific technology policy were found to be statistically significant and have a significant effect on performance. Second, the regression analysis has shown the moderation effects of R&D importance awareness between the capabilities of science and technology policies and their performance. On the other hand, a regression analysis showing that the capabilities of science and technology policies and network cooperation between the base regions were not significant, indicating that there is no effect of moderation of network cooperation between the base regions between the capabilities of science and technology policies and performance.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.3
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• pp.221-226
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• 2010

A rare isoflavone, 7, 8, 4'-trihydroxyisoflavone, was isolated from a 10-year-old fermented soybean food. 7, 8, 4'-trihydroxyisoflavone was isolated for the first time from a Korean fermented soybean food. Evaluation tests of biological activity showed significantly inhibition activity for free radical scavenging on both non-enzymatic (DPPH system) and enzymatic method (xanthine oxidase system). DPPH radical scavenging effect of 7, 8, 4'-trihydroxyisoflavone was similar with vitamin C in a dose-dependent manner. In xanthine oxidase (XO) system 7, 8, 4'-trihydroxyisoflavone showed superoxide radical inhibition activity of 50 % at a concentration of $6.6{\pm}0.4\;{\mu}M$. Also, the compound significantly suppressed cellular MMP-1 formation. These results suggest that 7, 8, 4'-trihydroxyisoflavone could be developed as a potential preventive or therapeutic agent against skin aging.

• Food Science and Preservation
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• v.23 no.7
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• pp.1065-1073
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• 2016

This study investigated the sensory attributes and quality characteristics of Fuji apples based on market commodity price to provide data for quality index of Fuji apples. Samples were purchased from the Garak market (Seoul Agro-Fisheries & Food Corporation) and divided into four groups depending on the price such as group A, B, C, D. There were no significant differences in their volume and weight among groups. In the soluble solid content and total free sugar, A and B group (high price) showed higher content than those of C and D (low price) group. And also, the A group and B, C, D group showed 386.29 mg% and 320.09~359.28 mg% in the total organic acid content, respectively. As an sensory evaluation results, A group and B group were evaluated higher score than those of C and D group in the uniformity of red color and glossiness of skin and unique apple sensory attributes using quantitative descriptive analysis. Consumer test showed similar to quantitative descriptive analysis results in the various sensory attributes. In the analysis results between quality characteristics and sensory attributes of Fuji apples, total acceptability was correlated positively with titratable acidity (r=0.58), soluble solid (r=0.89), soluble solid content/titratable acidity ratio (r=0.42), total free sugar (r=0.36) and total organic acid (r=0.38). Based on principal component analysis of apple's quality characteristics, apples were primary separated along the first principal component (pH, acidity, soluble solid content, total free sugar, organic acid), which accounted for 66.01% of total variance. In addition, principal component analysis of sensory evaluation revealed a total variance for the quantitative descriptive of 55. 65% and a total variance for the consumer test of 55.84%.